Workers commuting from Los Angeles County to Orange County, and from Orange County to Los Angeles County, represented the fourth and fifth largest flows of commuters across county lines, followed by three combinations in the Houston or Dallas metro areas in Texas, according to the Census Bureau.

Also in the top-10 for number of mega-commuters: Those who commute to New York from Pennsylvania's Monroe County — a 91-mile trip that takes about 2 hours each way.

The average travel time to work in the United States is 25.4 minutes, according to the U.S. Census Bureau.